This invention relates generally to numerically controlled machine tools, and more specifically, to a device for use on numerically controlled machine tools for measuring the relative cutting tool length to facilitate tool setting or, alternatively, to facilitate compensation of the machine tool control system for cutting tool offset.
During the operation of numerically controlled machine tools, such as horizontal or vertical spindle machine tools, it is often necessary to change machine cutting tools because of tool wear or breakage or because of engineering changes. Invariably, changing the cutting tool held in the machine tool spindle causes a change in the relative tool length since the new cutting tool is likely to be shorter or longer than the tool which it replaced. To maintain workpiece accuracy, it is necessary to set the new machine cutting tool to the same length as the old one, or to compensate the machine tool control system for cutting tool offset, that is, the deviation in cutting tool length. Unless either of these steps is undertaken following replacement of a cutting tool, workpiece accuracy can no longer be maintained. Heretofore, setting of cutting tool length has required the use of stand-alone optical tool setters. Although such tool setters permit very accurate setting of cutting tool length, they are not only very bulky, but also are relatively expensive. In contrast, the present invention concerns an apparatus for setting relative cutting tool lengths which is not only inexpensive and efficient in operation, but may also be used directly on the machine tool.
It is an object of the present invention to provide an apparatus for use on numerically controlled machine tools for setting relative cutting tool length.
It is another object of the present invention to provide a simple to operate and inexpensive to fabricate apparatus for use on numerically controlled machine tools for setting cutting tool length.